The transformation of promising two-dimensional (2D) materials into three-dimensional (3D) architectures is crucial for unlocking their full potential in advanced applications, as it enables enhanced structural integrity, tunable porosity, and improved functionality. However, a significant challenge in this process is preventing the undesired restacking of 2D nanosheets, which can severely limit their accessible surface area, hinder mass transport, and degrade their unique physicochemical properties. In this study, we investigate the electrochemically controlled formation of size-tunable 3D multiwalled graphene oxide (GO) mesotubes under shear flow conditions. Using a home-built electrochemical rheology setup, we systematically analyze the effects of applied potential on mesotube diameter, length, and band gap. Our findings reveal that increasing the positive potential enhances Al3+ ion dissolution, facilitating GO migration and leading to the formation of longer mesotubes, whereas negative potential suppresses mesotube growth by limiting Al3+ availability. Elemental and electrochemical analyses confirm the critical role of Al3+ ions as a structural binding bridge in the self-assembly process, directly influencing both mesotube morphology and electrochemical characteristics. This study provides valuable insights into the electrochemical regulation of GO mesotube formation, offering a viable strategy for tailoring mesotube dimensions and properties. The ability to precisely control mesotube growth expands their potential applications in energy storage, biosensing, and soft robotics, paving the way for novel electrochemically guided self-assembly techniques in graphene-based 3D materials.